1. Field of the Invention
The present invention relates to optical communication modules, and more particularly, relates to an optical communication module used for wavelength division multiplexing.
2. Description of the Related Art
In the field of optical communications, the transmission capacity per optical fiber cable has been increasing, and wavelength division multiplexing (WDM) as a communication method which realizes such increased transmission capacity is known. In wavelength division multiplexing, a plurality of optical signals with different wavelengths are simultaneously transmitted using a signal optical fiber.
An optical communication module used for wavelength division multiplexing is an optical transceiver. An optical transceiver used for wavelength division multiplexing includes a light emitting module including at least a plurality of light sources that emit light beams (optical signals) with different wavelengths, a lens that condense and collimates signals emitted from the light sources, and a multiplexing optical system that multiplexes optical signals condensed or collimated by the lens. Note that there are cases where the light emitting module is called a “transmitter optical module”, a “transmitter optical sub-assembly”, or the like.
Japanese Unexamined Patent Application Publication No. 2013-80900 (paragraphs [0056]-[0058], FIG. 11B) describes a light emitting module including a plurality of semiconductor lasers 44, a plurality of lens parts 46a that condense optical signals (signal light beams) emitted from the semiconductor lasers 44, and an optical multiplexer 48 in which an optical waveguide that multiplexes optical signals condensed by each of the lens parts 46a.